topic Re: SSH: The server has disconnected with an error. Too many authentication failures in ExtremeSwitching (VSP/Fabric Engine)

SSH: The server has disconnected with an error. Too many authentication failures

Jasper_R — Thu, 13 Jun 2019 16:25:05 GMT

Hi Guys,

I got the following error on two VSP 7200 switches. Got it solved on 1 switch by disabling and re-enabling SSH, but on the other switch, this doesn't work.

There are no active sessions, increasing the max-session allowed doesn't help, setting the timeout to 1 second to get "old" (there are none) session closed... But without any luck.

disabling rsa-auth did the trick on the last one, I could re-enable it after first ssh connections was successful.

Any one experience with this? Why does this happen?

Thanks!

Jasper

Re: SSH: The server has disconnected with an error. Too many authentication failures

Jasper_R — Thu, 13 Jun 2019 16:39:11 GMT

Also, XMC can't backup the switch when I re-enable the RSA-AUTH...

Re: SSH: The server has disconnected with an error. Too many authentication failures

M_Nees — Wed, 14 Jul 2021 22:25:34 GMT

Same Issue with VSP7400 - V8.3.1

As a workaround i enable telnet.

It seems that VOSS 8.3.x does not allow restart of SSH Server:

VSP7400:1(config)#no boot config flags sshd
Error: SSH cannot be disabled when IQAgent is enabled.
VSP7400:1(config)#

VSP7400:1(config)#no ssh
Error: SSH cannot be disabled when IQAgent is enabled.
VSP7400:1(config)#

Re: SSH: The server has disconnected with an error. Too many authentication failures

M_Nees — Thu, 15 Jul 2021 22:16:31 GMT

This are the steps to toggle SSH (with VOSS 8.3.1):

conf t
application
no iqagent enable
no ssh
ssh

But no success - error still the same!

Re: SSH: The server has disconnected with an error. Too many authentication failures

Dilraj_Singh_Kh — Fri, 23 Jul 2021 07:39:24 GMT

See if the below KB relates to your issue:

https://extremeportal.force.com/ExtrArticleDetail?an=000072396

Re: SSH: The server has disconnected with an error. Too many authentication failures

M_Nees — Fri, 23 Jul 2021 12:26:23 GMT

Hi Dilray,

your posted issue is related to problems with displaying a Login banner within SSH.

That is not realted to my “Too many authentication failures” error.

BR,

Matthias

Re: SSH: The server has disconnected with an error. Too many authentication failures

Dilraj_Singh_Kh — Fri, 23 Jul 2021 14:43:55 GMT

Sorry about that. Get a GTAC case opened and get it verified. This happens mostly due to incorrect/expired user or when incorrect cli login source is set on the device.

Re: SSH: The server has disconnected with an error. Too many authentication failures

M_Nees — Fri, 23 Jul 2021 15:51:04 GMT

GTAC Case open since more than 1 week - 02418250

Re: SSH: The server has disconnected with an error. Too many authentication failures

Dilraj_Singh_Kh — Tue, 27 Jul 2021 08:30:46 GMT

Got it. So it’s better to be handled by the GTAC. This seems to have crossed the point where it can be answered on community.

DILRAJ

Re: SSH: The server has disconnected with an error. Too many authentication failures

M_Nees — Fri, 30 Jul 2021 21:30:52 GMT

Today we can fix the issue with the excellent GTAC support.

Root Cause are empty SSH key files.

Deleting them and bouncing SSH will fix the problem.

delete .ssh/ssh_rsa.key
Are you sure (y/n) ? y
delete .ssh/ssh_dss.key
Are you sure (y/n) ? y

conf t

(config)#no boot config flags sshd
(config)#
(config)#
(config)#no ssh
(config)#
(config)#
(config)#boot config flags sshd
(config)#
(config)#ssh

(config)#sh log file tail
************************************************************************************
Command Execution Time: Fri Jul 30 16:13:47 2021 CEST
************************************************************************************
1 2021-07-30T16:13:46.994+02:00 XXXXXX CP1 - 0x000d8635 - 00000000 GlobalRouter SSH INFO SSH Host key generation is completed successfully
1 2021-07-30T16:13:40.391+02:00 XXXXXX CP1 - 0x000d8634 - 00000000 GlobalRouter SSH INFO SSH Host Key generation is in progress. SSH connections will not be processed till the key generation completes
1 2021-07-30T16:13:40.390+02:00 XXXXXX CP1 - 0x0000461f - 00000000 GlobalRouter SNMP INFO SSH server enabled
1 2021-07-30T16:13:40.390+02:00 XXXXXX CP1 - 0x000d861c - 00000000 GlobalRouter SSH INFO SSH Server Enabled

Re: SSH: The server has disconnected with an error. Too many authentication failures

Dilraj_Singh_Kh — Fri, 30 Jul 2021 22:07:52 GMT

Great. Thanks for posting the solution.